324 BRITISH FLOWERING PLANTS chap. 



extremes with intermediate gradations. Many species 

 have female as well as complete flowers, generally on 

 special, but sometimes, though rarely, on the same 

 plants. The female flowers are always smaller than the 

 others, though they vary considerably in size. The 

 nectar is generally protected from rain by hairs. The 

 capsules are generally upright, and the nutlets are 

 jerked out by the wind or by passing animals. In a 

 few genera the flower is nearly regular. 



Mentha (Mint) 



Complete flowers, protandrous, generally less numer- 

 ous than the smaller female ones. Some species dimor- 

 phous. Calyx regular or slightly two-lipped. Corolla 

 nearly regular. Stamens equal and erect. 



M. arvensis. — The corolla is lined with hairs which 

 protect the nectar ; the leaves are glabrous or hairy. 



M. aquatica includes a number of varieties and 

 forms, some of which are more or less glabrous, others 

 more or less hairy. 



M. rotundifolia has cut leaves, hairy above, tomen- 

 tose below, with branched hairs. 



M. Pulegium (Pennyroyal). — With us it is nearly 

 glabrous, but in the hot dry regions in the South of 

 Europe it develops a thick covering of hair as a pro- 

 tection against too rapid transpiration. 



Thymus (Thyme) 



In this genus the corolla is two-lipped, but not very 

 markedly so. 



T. Serpyllum. — The stamens and pistil project freely 

 from the flower. Besides the complete there are small 

 female flowers. In these, indeed, stamens occur, but 

 without fertile anthers. The filaments vary greatly 

 in length. Delpino found the plants near Florence 

 trimorphic — hermaphrodite, female, and male. Darwin, 

 however, in spite of careful search, never found any male 

 flowers in this country. The leaves are flat, ciliated at 



